Download Handout 19-2 Directed Reading

Handout 19-2
Features of the Ocean Floor
1. The shallow sea floor between the
shoreline and the deep-ocean bottom
is called the
• a. continental margin.
2. Continental margins are made up of
continental crust
• b. and a thick wedge of sediment.
3. The part of the continent covered by
water is called the
• c. continental shelf.
4. The continental shelf slopes gently
from the shoreline, and drops about
0.12 m every
• b. 100 m.
5. the average depth of the water
covering a continental shelf is about
• b. 60 m.
6. The continental shelf is part of the
• a. continental margin.
7. V-shaped valleys in the continental
shelf and continental slope are called
___________.
• submarine canyons
8. What is one place submarine
canyons are often found?
• Near the mouth of major rivers.
9. How can turbidity currents help
form submarine canyons?
• Turbidity currents carry sediment down the
continental slopes.
10. How do turbidity currents form?
• When earthquakes cause underwater
landslides
• When large sediment loads run down a slope
11. What is the name of the deepest
place in Earth’s crust?
• The Mariana Trench
12. Where is the deepest place in
Earth’s crust located?
• The Western Pacific Ocean
13. About how deep is the deepest
place in Earth’s crust?
• More than 11,000 meters deep
– 36,089 ft.
– 6.8 miles
14. In the deep-ocean basins, what is a
trench?
• A long, narrow and steep depression that
forms on the oceanfloor.
15. How do trenches form in the deepocean basins?
• Trenches form in deep ocean basins as a result
of subduction of a tectonic plate.
16. About half of the deep-ocean
basins are covered by __________.
• Abyssal plains
17. The flattest regions on Earth
are ____________
• Abyssal plains
18. Layers of fine _________ cover the
abyssal plains.
• sediment
19. How does the age of the oceanic
crust affect the thickness of sediments
on the abyssal plains?
• Older crust is generally covered with thicker
sediments than younger.
20. The most prominent features of
ocean basins are _________.
• mid-ocean ridges.
21. Mid-ocean ridges form underwater
________.
• mountain ranges.
22. What is one place where a midocean ridge rises above sea level?
• Iceland
23. Where do seamounts form?
• Near hotspots
• Areas of increased volcanic activity
24. guyot
25. hot spot
26. seamount
27. atoll
28. oceanic island
a. an area of increased volcanic
activity where seamounts form
b. submerged seamount with a
flat top
c. a seamount that rises above
the ocean
d. an oceanic island that is in
the process of being eroded into
a guyot
e. submerged volcanic
mountain taller than 1 km
The End!!!